The development of written language and its functions were studied for 236 second graders (from four locations in the surrounding Birmingham, Alabama area) in 6 traditional and 6 writing process classrooms. Pen pal letters to undergraduates and written samples were obtained from three students from each class. Writing process classrooms reflect writing experiences that include student-selected topics and choice of genre. Non-linear or recursive writing opportunities are included daily. Quantitative analysis assessed the children's written language development in spontaneous writing. Qualitative methods assessed the following functions of written language: (1) instrumental; (2) regulatory; (3) interpersonal; (4) personal (awareness of self); (5) heuristic; (6) imaginative; and (7) informative. A quasi-experimental design compared effectiveness of pen pal letters as strategies for written language development in the two types of classrooms. Children from the writing process classroom provided more decontextualized topics and appeared to have more ownership and voice. Teachers in writing process classrooms also appeared to have a better knowledge of the developmental process of writing and spelling. Pen pal letters do provide an opportunity for children to use multiple functions of language. Most of the children perceive their writing experiences as positive. Four tables and 1 figure present study data, and 45 references are included. (SLD)